This invention relates to a foldable cart, and more particularly to a foldable cart having hinged shelf members.
Most service carts, such as those used as food service carts in restaurants and institutions, or as used in health care institutions for carrying medical supplies, or as used in industry for carrying parts, supplies and products, have a plurality of rigid shelf members. These shelf members may be in the form of solid shelves or shelf rails for receiving receptacles, in which the cart and shelves are rigid and occupy the same amount of storage space as they do when being utilized.
Some service carts have a knock-down construction in which the parts may be disassembled for transportation and storage, but must be re-assembled before the cart can be utilized for its desired function. U.S. Pat. No. 3,536,016 issued to Chesley on Oct. 27, 1970 discloses a knock-down type of shelf cart.
Carts which are foldable or collapsible are also known, as illustrated in the following U.S. Pat. Nos.:
1,304,847; Blais et al; May 27, 1919; PA1 1,408,604; Kawa; Mar. 7, 1922; PA1 2,720,402; DePuy et al; Oct. 11, 1955; PA1 2,865,646; Kronhaus; Dec. 23, 1958; PA1 3,202,438; Panknin et al; Aug. 24, 1965; PA1 4,326,731; Woychio et al; Apr. 27, 1982.
The Blais et al U.S. Pat. No. 1,304,847 discloses a cart or rack having foldable shelves in which the hinged inner end portions of the shelves are relatively vertically stationary, while the outer end portions of the shelves are elevated when the end frames are collapsed.
The Kawa U.S. Pat. No. 1,408,604 discloses a rack for drying photographic prints including a single connector member 8 having hinged parts 9 and 10, the inner hinged ends of which fold upward as the uprights 5 collapse (FIG. 2).
In the DePuy et al U.S. Pat. No. 2,720,402, the shelf members or trays are always rigid as the end frames are pivotally collapsed against the shelves or trays.
Although the Kronhaus U.S. Pat. No. 2,865,646 discloses a foldable tea cart having vertically spaced pairs of shelf members pivotally connected to the end frames and also to each other so that the pivotally connected inner end portions of the shelf members are elevated during folding, nevertheless, no lift bar or guide bar is incorporated in the Kronhaus cart.
In the Panknin et al U.S. Pat. No. 3,202,438, the side wall members of the shelf structure are connected by a pair of pivotal cross braces for movement of the side frame members toward and away from each other. The posts incorporate a pair of vertical slots to permit the vertical travel of the upper pivotal ends of each of the cross braces.
The Woychio et al U.S. Pat. No. 4,326,731 discloses a folding cart having a pair of coplanar hinged shelf members which operates on a principal similar to the Kronhaus cart, and does not incorporate a lift or guide bar for manipulating the hinged shelves.
U.S. Pat. No. 638,100 of Kourtney, issued Nov. 28, 1899, discloses a folding baby carriage.
U.S. Pat. No. 1,198,431 issued to Forsyth on Sept. 19, 1916 discloses a foldable type shelf structure for a shoe rack.
U.S. Stevens U.S. Pat. No. 1,290,398, issued Jan. 7, 1919 discloses a foldable or knock-down type shelf structure used as an oat sprouter.